Field of the Invention
The present invention relates to gateway apparatuses, and more particularly, to a gateway apparatus that can control communication between an image processing apparatus connected to the gateway apparatus and an external apparatus.
Description of the Related Art
Instead of server software that is operated by a server so as to reduce the server introduction/management costs in a LAN (Local Area Network), so-called cloud applications are now widely spread. When executed with the use of a so-called cloud server connected to the Internet, a cloud application can provide various kinds of services to a user.
In some cloud system that provides a cloud application in a usable form, the cloud application provides various kinds of services while communicating with devices such as MFPs (Multi-Function Peripherals) or printers that are operated in a LAN in each corporation. In such a cloud system, communication from the cloud application to a device is conducted. This communication is to access an MFP or the like in an intranet from the Internet. Therefore, due to the function of a so-called firewall normally located on a boundary between the Internet and an intranet, communication cannot be conducted in some cases. In an environment where private IP addresses are allocated to MFPs, for example, the IP address of an MFP cannot be designated from the cloud application side, and communication cannot be conducted. In view of this, a gateway apparatus that relays communication between an apparatus on the Internet side and a device in a LAN is used.
A gateway apparatus is constantly connected to a management server that can be connected thereto via the Internet, and relayed communication between an apparatus such as a cloud server on the Internet side and an image processing apparatus in a LAN can be established based on a result of communication with the management server.
The power supply for such a gateway apparatus is sometimes cut off due to a maintenance activity or the like. In view of this, an alternate apparatus having an alternate function of a gateway apparatus is prepared beforehand. When the power supply is cut off, the function is transferred from the gateway apparatus to the alternate apparatus, so that relayed communication between an apparatus on the Internet side and a device in a LAN can be conducted via the alternate apparatus.
JP 2008-210358 A discloses a method by which the data necessary for an electronic circuit unit to recover is saved in a nonvolatile memory in a data processing apparatus after a cutoff of the primary power supply is detected as a trigger, until the voltage of the secondary power supply drops to the lower limit of the operation-guarantee voltage of the apparatus.
In some cases, a power supply for a gateway apparatus is unexpectedly cut off. For example, when a problem occurs in a gateway apparatus, a user might inadvertently switch off the power supply for the gateway apparatus, or an accidental power failure might occur. So as to maintain relayed communication in such a case, the function needs to be transferred to an alternate apparatus before the voltage of the secondary power supply becomes lower than the operation-guarantee voltage of the CPU, with a cutoff of the primary power supply being a trigger.
The period from a cutoff of the primary power supply to a drop of the voltage of the secondary power supply depends on power consumption in the gateway apparatus. Therefore, to complete a function transfer without fail, the processing to be performed in the gateway apparatus needs to be minimized. To minimize the processing, the method described below may be employed, for example.
In some cases, a gateway apparatus has both a main CPU and a sub CPU. A CPU that has a relatively high information processing capacity but has a relatively high lower limit of the operation-guarantee voltage may be used as the main CPU, and a CPU that has a relatively low information processing capacity but has a relatively low lower limit of the operation-guarantee voltage may be used as the sub CPU. In this case, the sub CPU can be made to perform the transfer operation.
As the alternate apparatus that serves as the transfer destination is determined beforehand, the information necessary for the transfer can be sent beforehand. Here, the necessary information for the transfer includes a list of devices such as image processing apparatuses to be managed by the gateway apparatus in such a manner that relayed communication can be conducted, the IP address of the management server, and the like.
However, such a method has the problems described below.
Specifically, the alternate apparatus might be unable to transfer the function, because the power supply for the alternate apparatus is off, or normal communication cannot be conducted due to a network failure, for example. The method by which the alternate apparatus that is to serve as the transfer destination is determined in advance cannot cope with such situations.
Also, in a case where only a transfer instruction is sent to the alternate apparatus, the communication being relayed at the moment is discarded. Therefore, if a transfer instruction is issued while printing is being performed based on information transmitted from a cloud server, for example, the print job being performed is discarded, and the printing needs to be resumed from the top of the job.
To solve the former problem, it is possible to employ a method by which a device that is suitable for the transfer is selected from among alternate apparatuses while the state of each alternate apparatus that can serve as a transfer destination is checked. By such a method, however, the load on the main CPU becomes larger, and the processing requires a longer period of time. Therefore, the voltage might run out during the processing, and the transfer process might not be performed.
To solve the latter problem, it is possible to employ a method by which a function transfer is performed after the relaying of the communication being relayed is completed. However, the voltage might run out before the relaying is completed, and the transfer process might not be performed.